Plural scale indicator



June 3, 1952 w. D. MAcGEoRGE r-:TAL 2,599,005

' PLURAL SCALE INDICATOR Filed April 7, 1948 3 Sheets-Sheet 1 2 I Eig- Q1 ATTORNEY June 3, 1952 w. D. MAcGEoRGE ETAL 2,599,005

PLURAL SCALE INDICATOR 1948 3 Sheets-Sheet 2 June 3, 1952 v w. D. MAGEoRGE ETAL 2,599,005

PLURAL SCALE INDICATOR Filed April 7, 194e s smug-sheet s /rssh /7 35 4 Fig. 9

Mw \E 5c 11e/r.

, GER Vo M0 TOE BEI VEN INVENToRs L19; vwlLAmm o. mAcGEoRGE AT TORNE V Patented June 3, 1952 l I l I I* .I

UNITED STATES PATENT charles E. I't'o'ejejsie, Jr., Priiiaaeipnia, Pf". asi: signets id Aiiiohifit Tereriitrwolitmf Qi., Ine., Philadelphia, Pal., a ooiiioiation if Peiiiieiflifania Application Alirill, 1948;, SMeriAa'V-jvo. l'fll ii cai'nis; (c1. iii-e351) This invention reia'tee to pinta-1 sea-1e inoiio'atoief, atea aeeoiidane viiit'i'i instant "ei teefr and' particularly to a clustered i'ridatr"etl alriged diti'r, inoi'itd a fragfit'vof. ghe'fro'gpn to dispiay selectively a plurality oi independent of the` iioiising Ydi' the indi'cato, iiitii the Iatt' codiii'ons at a c'oniinori point. l shjvij seeti'r'i.

As indieatiiiasystems nave deveioned iiitiietto', *5 Fig. iiep ente` a pian of' the' nioi'irit'ii ii eaen conditioned device ofy a piin iity of siien tne niagnifying iene of tneaevioe; en" the devices has had separate indicating' ineans' of osciiiatabie re'iieeto unit tiieeoi, mounted n rather* cumbe'isbme t'r'ef, sea'alte arid' ir'i-I aJ fragment of the rear panel of the hiiusiei',y iii-'i135 dependent boxes oiiiious'inee, necessarily ieqiii'itneiiiatter' shown" in sfeetion troi or condition-responsive variables are in-A tiariiy section of' the'indi'oiatoil ruin aesni'iy teeiated into a single unit and arianged foi seandv view" iectivej actuation to indieate anyy given" selected z'o'ntaiiy' of cditidn di' v'tiriiaibl'e;v t'o irprve' the cic'i'iii's in' 20 Fig. 8 epreseit's detail of indicating systems; to prei/'ide a composite inmizrioi anditenioiint in a` vfer'tio i dio'atoi for a niuiaiityiof more or'i'ese inoieiieniient Fie. Qjiepieefente a detaii oi t oontifoiiine or controlled devieesso arrareeoithat roi, and ite mount is coeieei gif of scales-is vietteiiinY tnefviewine window. physicalreiative movement of 'n'eiainiiatiire- The Fig'. 2 iiepresent'san iiiost'iatiife wiring: diaeiin motor; in'iiinning; ie oaiisj ny for' the` composite indi-eaten; Y ineain'natiiifeiofV aseoo train 'Fig'.,arepiesenttfa pianofitneiresiso'eive iii-f l coininonto al1-transmit in di'catiiiguiiitinoiiidiiieaoaiiiteddfiiiiia'etiie 65 seiedtetifsncees'sion iiiitii theo piito transformer equals and thereby cancels or nullies the output of the particular selected transmitter transformer. The distance traveled by the motor represents a function of the change of condition of the selected conditioned device, i. e. the instant value ofthe variable, as an indication thereof for signal and circuit balancing purposes. The motor may also, of course, be coupled With a control device affecting the regulation of the condition or variable modulating supply of the condition device, to modify same to restore a desired condition. Such a circuit with a single transmitter or pick-up unit in circuit with a single receiver unit, and the preferred forms of diierential transformers of the circuit are shown, illustratively, in the Hornfeck Patent No. 2,420,- 539, to which reference may be made for any necessary details not fully developed herein.

By the invention herein, a plurality of transmitters of pick-up units are provided, with one common receiver or balancing unit and one common motor, with means for selectively keying a selected transmitter to the common receiver, and with common means effecting a visual indication of the motor travel in effecting balance between the selected transmitter and the receiver unit, as a function of the initial imbalance, or variable change.

Referring now to Fig. 2, an illustrative circuit for an illustrative infinite number of transmitters is shown. Each transmitter transformer preferably comprises a pair of axially spaced secondaries I and II coupled in bucking relation, separated axially by a primary exciting coil I2. The coils are all hollow and axially aligned to form a central core aperture within which the armature mess I3 is positioned and has axial motion. The position of the armature is controlled by the position of the link I4 extending to and operative by a condition-responsive element operatively associated with a conditioned device. These devices, subject to varying conditions, may be of any desired sort, and the list of variables may be as recited or shown, for instance, in said Hornfeck patent mentioned, and a conditionresponsive element eiected by any one of said variables maybe considered as coupled to the actuating end of the link I4. Illustratively, the variables include ow, pressure, temperature, humidity, electromotive force and position responsive devices. When the armature is symmetrically disposed electrically and in the 4center of the transformer, the output of the coupled secondaries thereof is null, while relative physical movement of the armature of the transmitter in one direction from null gives an output of voltage of A phase, while movement in the other direction from null gives an output of voltage of B phase. When the armature in the transmitter is asymmetrical to furnish an output from its secondaries, and the armature of the receiver is asymmetrical in the proper direction to furnish a noutput from its secondaries equalV to and cancelling the output of the transmitter, the circuit is also balanced.

Let it be assumed. as purely illustrative, that a transformer I is operatively associated with a temperature-responsive device of a variably heated element such as the lai-metallic element l. That a transformer 2 is operatively associated with a pressure-responsive device, subjected to variable high pressures, such as a Bourdon tube 8, for instance, and that transformer n is operatively associated With a low pressure element such Y as bellows 9. Obviously, there may be any number of additional pick-up units between 2 and 11.. Although these may be independent elements, it will usually be preferred that they be associated with or in a common entity having plural variables as conditions which must be both watched and controlled. Illustratively, such an entity involving simultaneously a plurality of separate variables might be an oil-still or the like.

An amplifier unit I5 is provided into which the operating line voltage is fed from a suitable A. C. source, and into which the signal from each of the transmitters or pick-ups is fed in alternation selectively. A two phase reversible motor I6 is provided, having suitable gearing, including reduction gearing to be described, to drive the substantially transparent cylindrical drum I1 angularly between stop limits so that its travel is less than 360, and having leads from the resultant output of the amplifier, as well as leads to the line voltage for the circuit. A receiver differential transformer 3 is provided, formed of the central exciting primary I2 and the axially spaced secondaries lil' and II concentric with the axis of the primary coil, and having the physically movable armature I3 mounted on the link It', with the latter operatively coupled to and movable with the motor I6 or drum II, This coupling is in such manner that the physical disposition of the armature I 3' relative to the stator formed of the coils Ill', II' and I2 is a function of the angular position of the drum II, having a maximum position away from null in one direction at one limit of angular movement of the drum, and having a maximum position away from null in the other direction at the other limit of angular movement of the drum, as will be explained in connection with Fig. 3. A The circuit includes, in the preferred but illustrative embodiment, a biased single throw switch for each pick-up unit, preferably manually operated, identied respectively as SI, S2 and Sn, and each comprising for convenience four sets of contacts, corresponding sets in each switch being identied as an "b, 0, and d, respectively, with functions to be described, although contacts d of switch SI may have no function. Contacts a of all switches are all normally closed. Finger pieces or handles respectively 4, 5, and 611. are associated with the respective switches SI, S2 and Sn.

A plural position, shown illustratively as a three position reflector or mirror 20, to be described in detail later herein, is provided, having a plurality of electromagnets, illustratively two, respectively 2i and 22, each controlling one angular position of the mirror 2i), selectively fed by a D. C. output from the amplifier unit I5.

With the circuit arrangements as just recited, it will be seen that one primary lead and one secondary lead of each pair of coupled secondaries of each pick-up or transmitter I, 2 and n are common and are fed directly to the amplifier. The remaining primary lead from each pick-up is fed through the contacts c of its particular selector switch through the primary I2 of the balancing or receiver transformer 3 and then back to the preferred 6 v. A. C. source in the amplifier. The remaining secondary lead from each pick-up is fed through ycontacts b of its particular selector switch through the secondary of the balancing receiver transformer and then back to the amplifier input. A common line runs from a D. C. output of the amplifier unit to one contact of the pair of normally open contacts d of pick-up unit switches S2 and Sn, whilethe complemental contacto ci 'each 0I said pairs:- are connected respec tivelyr to the electromagnets 2l andi 22l through a common. lead back to the amplifying unit. l'.

. When the selector switches are. undepressed. or in. their' normal neutral position. to .which they are normally biased, the. normally closed. contacts' a. of all' of the; switches; are in series and. short out the external circuit so that the motor moves the indicator drum. and. the coupled receiver transformer. armature. to mid position or mid scale, where the balanced circuit will normallsr maintain` all of. the moving parts, including the armature of; the balancing receiver transformer'. This is in order to expedite the operation of the device so that uponA depressing anykey selector switch, the indicator drum will; only have tol move a maxi-'- mum ofV halt? scale under any operating cond-ie tions'.

isv any' selector switch. isdepressed by its. ringer control element to be identified laterherein, its pick-.up or transmitter unitv is connected into the measuring circuit; At the same; time, the com*- :nonv circuit through contacts a.: of: al1 switches-is opened. Of. cou-rse, but one selector switch is.. to be actuated. at a time, and if necessary interlockf, ing elements. (not shown) can. be used toinsure; the operation of but one switch at a. time;

As. each selector switch. having operative com tacts, d is'- depressed against. the bias, the said. conf taots d thereof are closed., which energizes: the.

appropriate electro. magnet: to swing the mirror in the manner to be.I described, at.. the, same time. that the particular transmitter is; placed in cir.- c-uit with the balancing receiver bycontacts b., in order to actuate-l the indicator. The pick-.up switch. SI and. all. other piclr-up units using. the sainescale as is associated with pick-up I, as noted, does: not actuate the mirror. In the circuit shown the electromagnet: 2|I controlled by switch S2 'rotates the mirrorcounterclockwise,

and all other pickfups having. the same scale as associated' with pick-up 2 will. have operative. connectionswith the same electromagnet. The. magnet 22 controlled by switch Sn rotates. the mirror. clockwise, and of course. allother circuits, usingl the same scale as that associated with. pickup. n will be operatively.` coupled to the. saine elec'-V tromagnet.

Thev indicator is housed in a housing. or box 23 having a front wall panel 24, through which. the. respective switch iingerelements. 4,: 5, 5,' and 611,-. extend as. shown, as: illustrative of any plurality of variables to. be indicated. A master switch25l controlling the circuit from the line. to the ampli-- iler. and motor is also. provided as shown.. The front panel 24 carries themotor and indicator as. sembly, to; be described in detail,` and at the top has. a verticallyl elongated relatively narrowv win.- dow. 26, which is preferably covered or closed; by' a ground glass plate 21, but this may be omittedfrornthe window or the element 21 can be a transparency if it is. desired to project indications; through. the Window on a target, wall, or. screen.. spaced from. the front panel. The housinghas the front panel 24 preferably arranged as a. door;y and. has side walls. 28, top and. bottom Walls. 2 9; and a, rear panelV or wall The mirror assembly, to bedescribed, either fixed or oscillatable as circum stances.. require, is mounted on the; rear panel.

Referring nowA to Figs. 3- and 6, a hollow cylindrical substantially transparent indicator druml'l is provided,.mounted for rotation by a shaft 32, journalled. horizontally in a supportingA gear train. frame 33,. mountedl on the inner surface of the. front panel. 24.. The reversible two' phase motorl 6 tti mountedA on: the.- gear train. frame 33 in position to have its drive. shaft 34 actuate.v a gear reduction train of gearsA and shafts 35i, journailed?` in the frame: 33:. The final pinion gear of: reduction. train 35 engages'. the: outer peripheryv of; the large gear 36, mounted on. the oscillatable shaft 32, to drive the drum. tlf. in. one direction or the. otherY aboutl its axis in shaft; 32. The position `of* the. drum. I1' will therefore be as a resuitzof a predetermined running of` the. motorv lli.. order' to effect-control of the receiver unit transformer 3,. the frame element 33, and the; parallel plate;- 33." carried thereby and forming pai-tof the train frame; are. provided with` aligned. horizontally spaced.v apertures. in which ilanged; linie-receiving and guiding bushings are mounted, respectively at. 31" and 38. Linkl it isf mounted; for horizontal axial motion. so: thaty the transformery armature.- i3.` carried' thereby'. is axially adjusted relative tothe transformer unit 3. 31I is merely a slidingl guide. forthev link', but the bushing 38 is. internally threaded to. receive the. threaded free end 40 of the link I4i". The. bushing 38 has; a reduced portion 4J` leading i toa shoulder 42. and upon which the spring washer- 43:4 is mounted forv frictional engagement; on frame..33. GearY 4Q has-.apressed tight fiton. axial extension 4J., locking the washer 43. to. the bush- 38, against; shoulder 42. The; gear. 44 is. in mesh:I with a worm; shaft 45. the; actuating. end of which. extends through the. frontpanel Z4. The llnlif. ltfcarries.: a driving: split gearA 46 in; per.-A manent. mesh with the teeth. of. the large gear 3d ot' the drum. l1 with one. portion keyed or affixed tothe shaft: I4. andi theacomplementalportion.af@- xedf. to the shaftbya, spring 3]: in such associa-V tion as to substantially obviate lash between gears. 46;- and; 3.6. When thelargev gear 36. rotates.. the threaded. link |42 is rotated through theaction of the; split gear: 465,. and the armature I3 is moved axially in and relative. to.r thestator of. the

transformer' 3... because the: bushing. 38 is heldV stationary by the friction. and. the said. bushing. is internally threaded., However.. when exactV and g minute adjustments 0I. the: armature I3 in the stator: of the transformer are required., with; the: motor. Ilstatictheory,v rotations of the Worm. shaft drives the small. gear 44 and thereby the bushing.

andthe armature motions thereafter-are tiedaccurately intoy the drum positionings. When is; realized that the. entire.` controlling.v motion. ofA the armature I3" may be of the order of. fg; of. aninch.

' or lessthenecessity for such accurate adjust-- mentszwill be Obvious;

The surface. of. the drum indicator is. calibrated. with at; least onecolumn ofrcalibrations' or a scale 48;... coordinated with. the,v percentage of angular motion# ascribed tol the.l drum in moving between its, angular limits and;` representing a predeter mined function. cf the variationsin condition of'` a.selected=. control device: and transmitter for op erative association with said scale. or with aplo-Y rallty of. independent pickqup units. if the variables.I respectively affecting; saine.y are of the same order as .to fit.I the. same scale 48: for proper. indi cations.` If but one scale`v is. use di the mirror 2U can. be stationary.. To; exemplify' the. possibilitiesA ofrthef system disclosed it. is preferred that there. bez a. plurality of rows. of'ealibrations, and; illustratively two rows and Eil'. on either.l side ot the central row or seriestMlt. noted, theremay'be an. inflnitefnumberot sensing or. transmitter cir-1 7 cuits, and allof those which can be' indicated by any single given scale on the indicator drum are arranged to selectively couple the instant circuit with the mirror assembly in such way as to expose the mirror to reflect the same scale reading p for each of the plurality upon or through window element 21.

Within the hollow indicator drum I1 there is mounted a light source 52, mounted on a support 52' and a pair of condensing lenses indicated by the block 53, so arranged that light passing simultaneously through the several rows ofcalibrations, is focused into a concentrated beam directed rearwardly of the housing and upon mirror 20. While, as will be seen, the angle of beam projection is only important from the standpoint of the reflection angle thereof, to 'be described, which is affected by the angle of mirror 20 to the vertical, it has been found satisfactory to project thebeam upwardly at an angle to the horizontal at about thereto against a vertical mirror 20. It will be understood that the projected beam will be of such width as to transmit all of the rows of calibrations at once, so as to be laterally of proper width for this purpose, while being vertically of great enough distance as to indicate enough of the calibrations as to enable a fair reading thereof. In other words, when the indicator drum is in the mid or null position, the central calibrations indicating 50% of the scale length or the mid point of the calibrations thereof will be in the vertical center of the projected beam, with enough additional calibrations verti-.

cally on both sides of the middle position as to facilitate instantaneous readings thereof, when suitably magnified and reflected, as will be described.

At the rear of the housing, a webbed bracket 55 is provided, having a vertical ange 56 secured to the rear wall panel 30, and having a forwardly extending horizontal portion 51 upon which is mounted a magnifying lens 58, adjustable axially for purposes of focusing, and arranged to be juxtaposed to the drum indicator I1` to receive the projected beam passing radially outwardly therefrom. At the rear the bracket 55 supports the rigid compound bracket comprised of -the forward lug 59 and the rearward, transversely extending magnet supports 60 and 6|, upon which, respectively, the electromagnets 2| and 22 are rigidly supported. The brackets 59 and arms 60 and 6l are substantially integral with a multiple pivot stationary housing comprising a front plate 49 terminating laterally in the vertically extending horizontally spaced rearwardlyA directedknife edges, respectively 62 and 63, evenly spaced on each side of the median line of the reilector unit, and having upper and lower rearwardly extending parallel plates or lugs 64 and 65 respectively. This last unit forms a substantially or effectively square box, the upper and lower lugs or plates of which form vertical guide stops for the plate to be described, and the lateral edges of which form pivot lines for the said' and lower parallel horizontal surfaces of such'.

vertical spacing as to slide between the plates or lugs 64 and 65 to'li'mit the relative vertical movements of the T plate in either direction, and provided with parallel vertical horizontally spaced notches 1i and 12.. A pin 13 .is anchored in the T plate and the pivot plate, and extends through the enlargedvaperture 14 in the rocking housing 49, and is connected resiliently by tension spring 15 to the xed lug 59. It will be seen that energization of the electromagnet 2l will pull the adjacent ear or plate porttion 61 toward itself to a rigid stop, causing the T plate to rock about knife edge 62 in socket recess 1l, as a pivot, causing the recess 12 to pull awayV from its stationary knife edge 63 to effect a fixed angular change of mirror position in moving clockwise about the operative fixed pivot 62. On the other hand, release of the electromagnet 2| will release the T plate to permit the mirror to swing counterclockwise about' the pivot knife edge 62 until both 'knife edges are engaged by their respective notches, when the mirror will beheld rigidly in its mid position. From this latter position, as will be clear, and as shown in Fig. 9, energization of the electromagnet 22 will cause attraction ofjthe magnetic plate Vportion 68, to swing the mirror mounting assembly counterclockwise about the knife edge 63, with positive stopped abutment against the magnet so that the mirror is rigidly mounted at a cocked angle between two horizontally spaced stops. There will be an auto- Vmatic subsequent clockwise movement of the mirror mounting assembly upon de-energization of the electromagnet, Vto rigidly support the mirror on two horizontally spaced stops against which it is held by the tension spring. The ac; curacy and stability and freedom from response to vibrations attained by the utilization of the spaced pivots and the rest of the rocking assembly will be evident.

It is preferred that a datum or hair line be furnished for the indicator which will'be permanently projected on the vertical center yof the window element 21 at all angular positions of the mirror. This is satisfactorilyv accomplished by providing an adjustable bracket Bil carrying the vertically narrow sheetof transparentplastic 8-I with a horizontal preferably bevelled free edge 82 disposed in the path of the beam projected from the drum indicator so as to cover approximately one-half of said beam. in such manner that by refractive effects the edge 82 of the interposed plastic sheet forms a thin shadow, functioning as a hair line for the projected beam. The datum line projector is disposed closely adjacent to the drum indicator, and is permanently fixed after once being adjusted and set. Of course, any other mode of presenting a datum line on the window element 21 may be used if desired.

It will be understood that the beam passing through the magnifying lens will be more or less symmetrical about a center line which is inclined upwardly predeterminedly from the horizontal, say, at approximately 15 as noted, and which angle of incidence of the center line on the vertical plane mirror will be equalled by the angle of reflection therefrom, so that the reiiected beam passes forwardly in the housing vertically clear of the drum assembly on the vertically elevated window element 21. At the same time, the beam from the magnifying lens is diverging by both vertical and horizontal angular divergence from the symmetrical center lineV thereof. so that it strikes or is incident upon the' i9? planefmir'ror 2D with v riou'sLanglesiof incidence, which are enhanced by ,the lfaddi-tiveanglesl of yreflections 'respectivelyattained by various por- .tionsY of the diverging beam so as 'to eiect a mag- -nication of the'beam both .vertically and horizontally relative to the vcenter thereof, asshown respectivelyin Figs. 1A and V.1B so that theinitial beam from the indicator drum is magnified in all directions whenlnally-incident uponthe inner surface of the frontipanel adjacent-tofand covering the Window element 21. The readings of therportions of the 'total beam permitted by .the instant angularity of the plane mirror 2d will'be with suchspread'between adjacent calibrations .as to be easily and vclearly read .and observed with reference to the .datum line. 1t will be understood lthat thescales as placed upon .the indicatordrum arev quite small andthe calibrations are quite close "together, certainly, Vat least, in contrast to -the ultimate projection thereof.

Inoperation, theindicator drum. is operatively coupled with as Vmany transmitter devices as necessary for the particular purposes required, and these Ymay be anywhere remote from the instrument, as all that is required is the variable responsive device and the coupled transmitter at the work, with electrical leads therefrom'to the instrument. The switches for the various variables will be mounted in the instrument, preferably, with finger 4operating elements at convenient points as indicated in the front of the'panel 24inFig. l. With the master switch 25 set, but with all pick-.up unit switches undepressed, the light source-52 will befunctioning,

andall of the .lens having been previously adjusted, the drum .indicator will remain in or be automatically swung toits substantially mid position, so that an instantaneous projection of the beam through the lenses. and against the mirror 20-inits xed un-cocked 'position and from the mirror against'the inner surface o'the panel`25 will show a magnified projection of the middle portion of the center scale at'the window-26. All other calibrations inthe beamy will be against the inner surface ofthe panel l2li but -willbe unobserved. This isV the normal neutral position of the parts.

vAs noted, `there will ybe as many key switches as there are variables to be considered, for-each ofwhich there isa pick-up-unit. This infinite range of numbers of nswitches and pick-up'units is indicated by the fact that after'pick-up units I and 2, the third one shown is designated as n. With .no `switch depressed, as previously `noted, the drum andtherefore thecoordinatedarmature -IS' is inthe 4null mid position. Let itbe assumed that at this point the finger element 4 associated with pick-up I is-depressed against its spring bias, whichplaces pick-up -I in vcircuit withthe amplifier I-5,motor i6, andthe receiver unit 3. If the relative Ldispositions of lthe armatures I3. and I3 are not identical in their respective stators, because Athere has beena departure of the instant condition of theconditioned device, to which pick-up I is responsive, there will be an output voltage from the pick-up which will run the motor I in the proper direction so as to move the indicator drum, while -atthe'same time the threaded'link I II' will -have :been vmoved axially Y-to'move the armature :I3 in its stator until the cancelling output lof the latter transformer balances that of the pick-up,at which point the motor I6 will stop andthe `drum will have moved `to-an angular position. representative of -the.initial unbalance .-as a function of the deviation-of thecondition affecting Vpick-up I.. In this. case the mirror yil is not moved .andthe magnified beam'striking .the .mirror is reiiected with enhanced magnication against the window velement-ZTI and against theinner surfaces. of .the Afront'vvall on` each side thereof. .Assoonasnthe rdepressed switch .4 is released, .the initialnormal vsetting-of the instrument .ta-.kes place, .andthe drum I7, if previously .moved .returns .automatically toward the mid .position or setting.

yWhen switch 5 is depressed the pick-.up unit 2 .is placed in circuit with the amplifier, rnotr and receiver 3, Aand if unbalance exists between the twov transformers themotor will beactuated and the drum turned until the receiver armature has vbeen again moved toward cancelling out the unbalance caused Vby the pick-upresponse .to the instantcondition. In thisy .'case, the Yelectromagnet ZI wllbeactuated also, :and the mirror given a cock or angular 4change so astoreflect the pattern of the illustrativ'eithree sets of calibrations asymmetrically of the 4window,..so thatthe calibrations 5I will' bethe ones appearingon the ground glass 2l, or transmitted through the window upon a target spacedfrom the instrument.

There m-ay be a number of pick-.ups affected vby individual variables of .a plurality of variables, which may be moreor less related, each pick-up respectively having finger elements 'of switches operablefrom .the front of the panel and selectively energized to cause Vtransmission of thereilecton of the same scale, modiedin each instant case by the particular Ydegreeof variation of the instant variable. These .respective variablesare .each capable of 4being represented by thesameset of calibrations. To illustrate. the point it will be assumed that .the 'finger element ofswitch 5f, shown in Fig. l, actuates theswiteh of a pick-up unit (not shown) arranged .for indications by the lsame set of vcalibrations v5I asis. brought into operation by switch 5, in which case the same electromagnet `2l 4will be actuated to swing or cock the mirror 20ft`o project the Vsame 4setof calibrations'SI against the window element 2l, even though in the illustrative case .the .particular variable for switch 5 may be ata diierent condition from that ascertained .of `the .pick-up unit associated with switch 5. y

`It-willbeseen .thata controlling operator can stand ina single point and. by merely depressing appropriatekeys or switches, Vcan progressively have an indication of the condition of a multitu'deA of .variables throughs, common sight'opening, by clustering the responsive devices in the common housing disclosed.

The simplicity, eiciencyand.advtantages of the invention :will beapparent.

Matter disclosed but` not ,claimedhereinis being claimed ein a continuationein-partl application, Ser. .No. 208,389, led January 29, 1951.

Having thus described. our inventiomwe claim:

1.-A multiple indicator comprising vla ,circuit network, plural -meansin the networkioroper'ative association .respectively with .a .plurality .of variables, Aa plurality of .selector circuitcontrollers lin the.network, an electricservomotor inthe network and arranged tobe operatedby any selected one of said .plural meanswhen .the appropriate selectorfcircuit controller Ais-actuated, va viewing screen, an indicator Vhavingya plurality of rows of calibrations in Amutually spaced relation transversely of the rovrs, means l1 mounting the indicator in driven relation to said motor to move the indicator substantially in the line of said rows to a setting in which a selected scale of said plurality is positioned as a function ofthe condition of a given selected variable determined by actuation of a given selected controller, light means for projecting a portion of v,all of saidv scales simultaneously from said indicator toward said viewing screen in a beam of `larger, transverse area thanl said screen, said light means including means for predetermining and varying the angle of incidence of said projected beam relative to said screen so that selectively any single selected scale of said plu= `and projecting .toward the screen a beam comprising a portion of each of the said plurality and of greater width than-the width of the screen, and electrical means controlled by said `switches for predetermining the specic necessary angle of incidence of said beam relative to the screen of a plurality of such angles whereby a selected one only of said plurality of scales in incident on the viewing screen.

3. AA multiple indicator comprising an arcuate cylindrical indicator having a plurality of scales extending respectively angularly of the arcuate portion in transversely spaced rows, a datum line common to all of the scales, an electric servomotor in driving relation to said indicator to position same, a viewing screen, light means for projecting angular portions of all of said scales, an Yoptical system including a reflector--for magnifying and reecting said projected portions toward'said viewing screen at a given angle of incidence thereon and in a beam Wider than the screen, whereby with said given angle of incidence but a single scale of the reflected portions of the plurality can properly be viewed therein, and means for varying the angle of the reflector of said optical system relative to the light means to change the given angle of incidence'to a different angle to eiectively establish the beam relative to said screen so as to cause a different selected single scale of said plurality to be incident upon said viewing screen.

4. An electric servomotor driven indicator having a plurality of scales, a reiiector, a viewing screen, and means for optically magnifying and projecting a portion of all of said scales towardV the reflector forA incidence thereon, means mounting the reflector for a setting relative to the projection at which the projected portions of said scales are reflected toward and on said screen, said screen being smaller than said reected portions of said plurality of scales whereby a given single scale only of said plurality of scales is incident upon and readable on the screen, and means for selectively moving' said reflector on its mounting to modify the said *setting to change the effective angle of incidence of the reflected plurality of scales relative to said screen whereby a predeterminedly diierent scale 12 only of' said 'plurality of scales viewable upon said screen.

5; An electric servomotor driven indicator having a plurality of scales, a reflector, a viewing screen, and means for optically magnifying and projecting a, portion of all of said scales toward the reflector for incidence thereon, means mounting the reflector for a setting relative to the projection at which the projected portions of said scales are reiected towai'd and on saidV screen, said screen being smaller than said reiiected portions of said plurality of scales whereby a given single scale only of said plurality of scales is incidentV upon and readable on said screen, and means Vfor selectively mov ing said reflector on its mounting to modify the said setting to change the effective angle of incidence of the refiectedplurality of scales relative to said screen whereby a predeterminedly different scale only of said plurality of scales is incident and viewable upon said screen, said means for moving said reflector comprising a plurality of selectively energizable electro-magnetic units.

6. An electric servomotor driven indicator having a plurality of scales, a reector, a viewing screen, and means for optically magnifying and projecting a portion of all of said scales toward the reflector for incidence thereon, means mounting the reflector for a setting relative to the projection at which the projected portions of said scales are reiiected toward and on said screen, said screen being smaller than said reiiected portions of said plurality of scales whereby a given single scale only of said plurality of scales is incident upon and readable on said screen, andmeans for selectively mov" ing said reector on its mounting to modify the said setting to change theeffective angle of incidence of the reflected plurality of scales relais incident and Y tive to said screen wherebyra predeterminedly different scale only of said plurality of scales is incident and viewable upon said screen, said means for moving Ysaid reflector comprising a plurality of selectively energizable electro-mag"- netic units, said mounting means comprising a Xed two'point support, a, plate having wings', resilient means holding said two point plate against the support to establishrsaid given angle of incidence, electro-magnetic means between the support and said respective wings operative to tilt the plate and reector.

7. A multiple scale indicator comprising an electric servomotor, an indicator positioned by the running of the motor and bearing a plurality of scales, a viewing screen, means for projecting a light pattern containing portions of a plurality of said scales larger than said screen toward and overlapping said screen, said pattern projection normally having an angle relative to the screen such that a portion of only a'single predetermined scale of the projected plurality is incident and viewable upon the screen, an input source, a circuit controller operative to couple the input source and theV motor, and electrical means 'responsive to actuation of said circuit controller to change the normal angular incidence of said pattern on said screen to estab-v lish a different overlap thereon whereby a portion of another scale of said Yprojected plurality is solely incident and viewablev on said screen.

8. .A n optical indication system, comprising movable means bearing Va plurality of separate parallel transversely spaced visible scales, a viewing screen comprising an opaque area containing and transversely framing a sight vlindow, means for generating and for projecting from said movable means against said viewing screen a light beam containing at the viewing screen a light pattern of magnified portions of all of said scales, said beam having a generally symmetrically disposed effective focal axis in'- tersecting said viewing screen, means for controlling the angles of incidence of said effective focal axis relative to said screen between an instantaneously maintained first angle at which a portion of one selected single magnified scale only of the plurality of scales in said pattern is incident upon and framed in said sight window and an instantaneously maintained second predeterminedly different angle at which a portion of another selected single magnified scale only of the plurality of scales in said pattern is incident upon and framed in said sight window, said controlled change in angles of incidence being transverse of the magnied scales in said pattern, means mounting the movable means for movement in the general line of the respective visible scales thereon, and electric servomotor means for moving and positioning said movable means to determine the portions of all of the scales appearing in said pattern.

9. An indication system as recited in claim 8, in which the means for projecting and the means for controlling incorporate an oscillatable mirror.

10. An indication system as recited in claim 8, incorporating an electrical network with which said electric servomotor is operatively coupled, and in which the respective means for projecting and for controlling incorporate an oscillatable mirror, and said network including electromagnetic means for controllably oscillating said mirror, and common means are provided in the network for actuating said servomotor to position the movable means as a related function of one given visible scale thereon 14 and for controlling the electromagnetic means to eect a selected angle of incidence of the focal axis of said beam to said screen, whereby the magnified portion of said given scale only in the pattern of the plurality of scales is framed in said Window.

11.An indication system as recited in claim 8 in which means are provided for controlling the servomotor means to position the movable means as a relatedfunction of one selected visible scale thereof, and in which the controlling means effects that angle of incidence of the beam at which the single said selected visible scale in the projected pattern in the light beam is framed in said window.

WILLIAM DEAN .MACGEORGE CHARLES E. ROESSLER, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 393,756 Griscom Dec. 4, 1888 1,361,676 Brewer Dec. 7, 1920 1,451,166 McCarthy Apr. 10, 1923 1,487,514 Goss Mar. 18, 1924 1,641,199 Roucka Sept. 7, 1927 1,660,886 Randall Feb. 28, 1928 1,715,074 Platten May 28, 1929 1,880,415 Carroll Oct. 4, 1932 1,882,772 Carroll Oct. 18, 1932 1,913,874 Folberth June 13, 1933 1,933,650 Bascom Nov. 7, 1933 2,126,059 Turner Aug. 9, 1938 2,154,066 De GierS Apr. 11, 1939 2,207,744 Larson July 16, 1940 2,226,441 Paul Dec. 24, 1940 2,328,320 Baruch Aug. 31, 1943 2,421,077 Miller May 27, 1947 2,504,386 Brady Apr. 18, 1950 

